Bidirectional Piezo MEMS Element for Faster Deflection

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Solution Overview

Problem

Existing micromechanical elements in microelectromechanical transducers are limited to unidirectional quasi-static motion, restricting their ability to achieve target amplitudes and maximum deflection quickly and efficiently.

Innovation Solution

A bidirectional micromechanical element design featuring piezoelectric elements arranged on opposite sides of a substrate's neutral axis, with optional cavities and passivation layers, allowing for faster amplitude attainment and increased maximum deflection through flexible bending behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If piezoelectric elements are arranged only on one side of the neutral fiber, then the structure is simpler, but the motion is limited to unidirectional quasi-static motion and cannot achieve target amplitude quickly

Engineering Contradiction:

Improvebidirectional motion capabilityVSAvoidpiezoelectric element arrangement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The support layer is segmented into regions with piezoelectric elements arranged on opposite sides of the neutral fiber, allowing independent control of different segments to achieve bidirectional motion while maintaining structural simplicity in each segment

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The piezoelectric elements are arranged in a planar distribution on both sides of the neutral fiber rather than stacked vertically, enabling bidirectional bending motion in the longitudinal direction while maintaining a relatively simple three-dimensional structure

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Strength

If the support layer is made more flexible to increase maximum amplitude, then the maximum deflection increases, but the structural stability and manufacturing precision may deteriorate

Engineering Contradiction:

Improvemaximum deflection amplitudeVSAvoidsubstrate fabrication accuracy

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The neutral fiber position is optimized within the support layer thickness, and the piezoelectric element arrangement parameters (distance from neutral fiber, orientation) are adjusted to achieve the desired balance between flexibility for large deflection and stability for manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The support layer is constructed as a composite structure with the neutral fiber providing structural stability and the piezoelectric elements providing controlled flexibility, allowing the system to achieve both manufacturing precision and large deflection capability

Inventive Principle:

Principle #40Composite materials

3Stability of the object's composition

If piezoelectric elements are placed closer to the neutral fiber to reduce stress, then the structural integrity improves, but the bending moment and deflection capability decrease

Engineering Contradiction:

Improvesubstrate structural integrityVSAvoidbending moment

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The piezoelectric elements are pre-positioned at optimized distances from the neutral fiber during manufacturing, establishing the initial stress distribution and bending moment characteristics before operation, allowing the structure to maintain integrity while achieving required deflection

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Different regions of the support layer have piezoelectric elements arranged at different distances from the neutral fiber, creating local variations in stress and bending moment distribution that optimize both structural integrity and deflection capability in different areas

Inventive Principle:

Principle #3Local quality

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables rapid and flexible bidirectional motion, enhancing the performance of microelectromechanical transducers by allowing for larger deflection strokes and differential sensing capabilities.

Implementation Method 1

a first piezoelectric element (110) arranged on a first side (120) of the neutral fiber (125) of the support layer (105)... a second piezoelectric element (115) arranged on a second side (130) of the neutral fiber (125)

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP4420496B1Micromechanical element for a microelectromechanical transducer, method for producing a micromechanical element, method for operating a micromechanical element, device and microelectromechanical transducer

Publication Date: 2026.01.28 ROBERT BOSCH GMBH

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AI summary

The approach presented here relates to a micromechanical element (100) for a microelectromechanical transducer, the micromechanical element (100) comprising a carrier layer (105) shaped as a bending beam or membrane, a first piezoelement (110) arranged on a first side (120) of the neutral axis (125) of the carrier layer (105), and a second piezoelement (115) arranged on a second side (130) of the neutral axis (125) of the carrier layer (105), the second side (130) being opposite the first side (120).